Centos 6.2-Apache 2-PHP 5-执行空白结果

Question

I have one issue executing 'ping' on PHP, I received a blank result but if I execute other command like a 'whoami' I received a right result, Could you help me please? any Idea?

<?php
exec('ping google.com', $output);
echo $output;
//Result: 
?>

<?php
exec('whoami', $output);
echo $output;
//Result: apache
?>

Thanks

Note: Maybe can be some from apache config? or php config? or linux permission?

Answer 1

I'm guessing it's cos the default behavoir of ping is to never stop. It keeps going until you kill it.

man ping says " -c count Stop after sending count ECHO_REQUEST packets. With deadline option, ping waits for count ECHO_REPLY packets, until the timeout expires."

Try adding options to limit pings run-time and see if you get a result.

Answer 2

Try this code.

<?php
function GetPing($ip=NULL) {
 if(empty($ip)) {$ip = $_SERVER['REMOTE_ADDR'];}
 if(getenv("OS")=="Windows_NT") {
  $exec = exec("ping -n 3 -l 64 ".$ip);
  return end(explode(" ", $exec ));
 }
 else {
  $exec = exec("ping -c 3 -s 64 -t 64 ".$ip);
  $array = explode("/", end(explode("=", $exec )) );
  return ceil($array[1]) . 'ms';
 }
}

echo GetPing();
?>

Answer 3

You can also try this one

<?php
$output = shell_exec('ping google.com');
echo "<pre>$output</pre>";
?>